Abstract

The radioactive agents used in the nuclear medical field are called radiopharmaceuticals and are required to exhibit high and specific localization of radioactivity into target tissue. Among radionuclides used in radiopharmaceuticals 99mTc plays an important role in widespread applications. The preeminence of 99mTc is attributable to its optimal nuclear properties of a short half-life and a gamma photon emission of 140 keV, which is suitable for high-efficiency detection and which results in low radiation exposure to the patient. Radionuclides in nuclear medicine are all synthetic and fall into four categories namely, generator produced, thermal neutron reactor produced, cyclotron produced and pile produced. Radiopharmaceuticals undergo a very lengthy and expensive regulatory process as well as extensive chemical and physical testing (pH, isotonicity and chemical parameters) to insure that the final product is sterile, pyrogen free, safe for human use and is efficacious. These include both animal and human studies prior to release of the product for sale. Clinical application of radioactive diagnostic and therapeutic agents constitutes one of the great advances in nuclear medicine. Various radiopharmaceuticals have been applied clinically in the diagnosis of various malignant and benign conditions. This article highlights the preparation, evaluation and applications of radiopharmaceutical preparations; which contain such useful radio atoms.